Dokument-ID Dokumenttyp Verfasser/Autoren Herausgeber Haupttitel Abstract Auflage Verlagsort Verlag Erscheinungsjahr Seitenzahl Schriftenreihe Titel Schriftenreihe Bandzahl ISBN Quelle der Hochschulschrift Konferenzname Quelle:Titel Quelle:Jahrgang Quelle:Heftnummer Quelle:Erste Seite Quelle:Letzte Seite URN DOI Abteilungen OPUS4-38572 Wissenschaftlicher Artikel Coelho, Catarina; Foti, Alessandro; Hartmann, Tobias; Santos-Silva, Teresa; Leimkühler, Silke; Romao, Maria Joao Structural insights into xenobiotic and inhibitor binding to human aldehyde oxidase Aldehyde oxidase (AOX) is a xanthine oxidase (XO)-related enzyme with emerging importance due to its role in the metabolism of drugs and xenobiotics. We report the first crystal structures of human AOX1, substrate free (2.6-angstrom resolution) and in complex with the substrate phthalazine and the inhibitor thioridazine (2.7-angstrom resolution). Analysis of the protein active site combined with steady-state kinetic studies highlight the unique features, including binding and substrate orientation at the active site, that characterize human AOX1 as an important drug-metabolizing enzyme. Structural analysis of the complex with the noncompetitive inhibitor thioridazine revealed a new, unexpected and fully occupied inhibitor-binding site that is structurally conserved among mammalian AOXs and XO. The new structural insights into the catalytic and inhibition mechanisms of human AOX that we now report will be of great value for the rational analysis of clinical drug interactions involving inhibition of AOX1 and for the prediction and design of AOX-stable putative drugs. New York Nature Publ. Group 2015 7 Nature chemical biology 11 10 779 + 10.1038/NCHEMBIO.1895 Institut für Biochemie und Biologie OPUS4-39029 Wissenschaftlicher Artikel Contin, Andrea; Frasca, Stefano; Vivekananthan, Jeevanthi; Leimkühler, Silke; Wollenberger, Ursula; Plumere, Nicolas; Schuhmann, Wolfgang A pH Responsive Redox Hydrogel for Electrochemical Detection of Redox Silent Biocatalytic Processes. Control of Hydrogel Solvation The control of bioelectrocatalytic processes by external stimuli for the indirect detection of non-redox active species was achieved using an esterase and a redox enzyme both integrated within a redox hydrogel. The poly( vinyl) imidazole Os(bpy)(2)Cl hydrogel displays pH-responsive properties. The esterase catalysed reaction leads to a local pH decrease causing protonation of imidazole moieties thus increasing hydrogel solvation and mobility of the tethered Os-complexes. This is the key step to enable improved electron transfer between an aldehyde oxidoreductase and the polymer-bound Os-complexes. The off-on switch is further integrated in a biofuel cell system for self-powered signal generation. Weinheim Wiley-VCH 2015 7 Electroanalysis : an international journal devoted to fundamental and practical aspects of electroanalysis 27 4 938 944 10.1002/elan.201400621 Institut für Biochemie und Biologie OPUS4-38586 Wissenschaftlicher Artikel Hahn, Aaron; Engelhard, Christopher; Reschke, Stefan; Teutloff, Christian; Bittl, Robert; Leimkühler, Silke; Risse, Thomas Structural Insights into the Incorporation of the Mo Cofactor into Sulfite Oxidase from Site-Directed Spin Labeling Mononuclear molybdoenzymes catalyze a broad range of redox reactions and are highly conserved in all kingdoms of life. This study addresses the question of how the Mo cofactor (Moco) is incorporated into the apo form of human sulfite oxidase (hSO) by using site-directed spin labeling to determine intramolecular distances in the nanometer range. Comparative measurements of the holo and apo forms of hSO enabled the localization of the corresponding structural changes, which are localized to a short loop (residues 263-273) of the Moco-containing domain. A flap-like movement of the loop provides access to the Moco binding-pocket in the apo form of the protein and explains the earlier studies on the in vitro reconstitution of apo-hSO with Moco. Remarkably, the loop motif can be found in a variety of structurally similar molybdoenzymes among various organisms, thus suggesting a common mechanism of Moco incorporation. Weinheim Wiley-VCH 2015 5 Angewandte Chemie : a journal of the Gesellschaft Deutscher Chemiker ; International edition 54 40 11865 11869 10.1002/anie.201504772 Institut für Biochemie und Biologie OPUS4-38659 Review Hartmann, Tobias; Schwanhold, Nadine; Leimkühler, Silke Assembly and catalysis of molybdenum or tungsten-containing formate dehydrogenases from bacteria The global carbon cycle depends on the biological transformations of C-1 compounds, which include the reductive incorporation of CO2 into organic molecules (e.g. in photosynthesis and other autotrophic pathways), in addition to the production of CO2 from formate, a reaction that is catalyzed by formate dehydrogenases (FDHs). FDHs catalyze, in general, the oxidation of formate to CO2 and H+. However, selected enzymes were identified to act as CO2 reductases, which are able to reduce CO2 to formate under physiological conditions. This reaction is of interest for the generation of formate as a convenient storage form of H-2 for future applications. Cofactor-containing FDHs are found in anaerobic bacteria and archaea, in addition to facultative anaerobic or aerobic bacteria. These enzymes are highly diverse and employ different cofactors such as the molybdenum cofactor (Moco), FeS clusters and flavins, or cytochromes. Some enzymes include tungsten (W) in place of molybdenum (Mo) at the active site. For catalytic activity, a selenocysteine (SeCys) or cysteine (Cys) ligand at the Mo atom in the active site is essential for the reaction. This review will focus on the characterization of Mo- and W-containing FDHs from bacteria, their active site structure, subunit compositions and its proposed catalytic mechanism. We will give an overview on the different mechanisms of substrate conversion available so far, in addition to providing an outlook on bio-applications of FDHs. This article is part of a Special Issue entitled: Cofactor-dependent proteins: evolution, chemical diversity and bio-applications. (C) 2014 Elsevier B.V. All rights reserved. Amsterdam Elsevier 2015 11 Biochimica et biophysica acta : Proteins and proteomics 1854 9 1090 1100 10.1016/j.bbapap.2014.12.006 Institut für Biochemie und Biologie OPUS4-38694 Wissenschaftlicher Artikel Herter, Susanne; McKenna, Shane M.; Frazer, Andrew R.; Leimkühler, Silke; Carnell, Andrew J.; Turner, Nicholas J. Galactose Oxidase Variants for the Oxidation of Amino Alcohols in Enzyme Cascade Synthesis The use of selected engineered galactose oxidase (GOase) variants for the oxidation of amino alcohols to aldehydes under mild conditions in aqueous systems is reported. GOase variant F-2 catalyses the regioselective oxidation of N-carbobenzyloxy (Cbz)-protected 3-amino-1,2-propanediol to the corresponding -hydroxyaldehyde which was then used in an aldolase reaction. Another variant, M3-5, was found to exhibit activity towards free and N-Cbz-protected aliphatic and aromatic amino alcohols allowing the synthesis of lactams such as 3,4-dihydronaphthalen-1(2H)-one, 2-pyrrolidone and valerolactam in one-pot tandem reactions with xanthine dehydrogenase (XDH) or aldehyde oxidase (PaoABC). Weinheim Wiley-VCH 2015 5 ChemCatChem : heterogeneous & homogeneous & bio- & nano-catalysis ; a journal of ChemPubSoc Europe 7 15 2313 2317 10.1002/cctc.201500218 Institut für Biochemie und Biologie OPUS4-10227 misc McKenna, Shane M.; Leimkühler, Silke; Herter, Susanne; Turner, Nicholas J.; Carnell, Andrew J. Enzyme cascade reactions A one-pot tandem enzyme reaction using galactose oxidase M3-5 and aldehyde oxidase PaoABC was used to convert hydroxymethylfurfural (HMF) to the pure bioplastics precursor FDCA in 74% isolated yield. A range of alcohols was also converted to carboxylic acids in high yield under mild conditions. 2015 5 3271 3275 urn:nbn:de:kobv:517-opus4-102271 Institut für Biochemie und Biologie OPUS4-39341 Wissenschaftlicher Artikel McKenna, Shane M.; Leimkühler, Silke; Herter, Susanne; Turner, Nicholas J.; Carnell, Andrew J. Enzyme cascade reactions: synthesis of furandicarboxylic acid (FDCA) and carboxylic acids using oxidases in tandem A one-pot tandem enzyme reaction using galactose oxidase M3-5 and aldehyde oxidase PaoABC was used to convert hydroxymethylfurfural (HMF) to the pure bioplastics precursor FDCA in 74% isolated yield. A range of alcohols was also converted to carboxylic acids in high yield under mild conditions. Cambridge Royal Society of Chemistry 2015 5 Green chemistry : an international journal and green chemistry resource 17 6 3271 3275 10.1039/c5gc00707k Institut für Biochemie und Biologie OPUS4-39127 Review Mendel, Ralf R.; Leimkühler, Silke The biosynthesis of the molybdenum cofactors The biosynthesis of the molybdenum cofactors (Moco) is an ancient, ubiquitous, and highly conserved pathway leading to the biochemical activation of molybdenum. Moco is the essential component of a group of redox enzymes, which are diverse in terms of their phylogenetic distribution and their architectures, both at the overall level and in their catalytic geometry. A wide variety of transformations are catalyzed by these enzymes at carbon, sulfur and nitrogen atoms, which include the transfer of an oxo group or two electrons to or from the substrate. More than 50 molybdoenzymes were identified to date. In all molybdoenzymes except nitrogenase, molybdenum is coordinated to a dithiolene group on the 6-alkyl side chain of a pterin called molybdopterin (MPT). The biosynthesis of Moco can be divided into three general steps, with a fourth one present only in bacteria and archaea: (1) formation of the cyclic pyranopterin monophosphate, (2) formation of MPT, (3) insertion of molybdenum into molybdopterin to form Moco, and (4) additional modification of Moco in bacteria with the attachment of a nucleotide to the phosphate group of MPT, forming the dinucleotide variant of Moco. This review will focus on the biosynthesis of Moco in bacteria, humans and plants. New York Springer 2015 11 Journal of biological inorganic chemistry 20 2 337 347 10.1007/s00775-014-1173-y Institut für Biochemie und Biologie OPUS4-39010 Wissenschaftlicher Artikel Schrapers, Peer; Hartmann, Tobias; Kositzki, Ramona; Dau, Holger; Reschke, Stefan; Schulzke, Carola; Leimkühler, Silke; Haumann, Michael 'Sulfido and Cysteine Ligation Changes at the Molybdenum Cofactor during Substrate Conversion by Formate Dehydrogenase (FDH) from Rhodobacter capsulatus Formate dehydrogenase (FDH) enzymes are attractive catalysts for potential carbon dioxide conversion applications. The FDH from Rhodobacter capsulatus (RcFDH) binds a bis-molybdopterin-guanine-dinucleotide (bis-MGD) cofactor, facilitating reversible formate (HCOO-) to CO2 oxidation. We characterized the molecular structure of the active site of wildtype RcFDH and protein variants using X-ray absorption spectroscopy (XAS) at the Mo K-edge. This approach has revealed concomitant binding of a sulfido ligand (Mo=S) and a conserved cysteine residue (S(Cys386)) to Mo(VI) in the active oxidized molybdenum cofactor (Moco), retention of such a coordination motif at Mo(V) in a chemically reduced enzyme, and replacement of only the S(Cys386) ligand by an oxygen of formate upon Mo(IV) formation. The lack of a Mo=S bond in RcFDH expressed in the absence of FdsC implies specific metal sulfuration by this bis-MGD binding chaperone. This process still functioned in the Cys386Ser variant, showing no Mo-S(Cys386) ligand, but retaining a Mo=S bond. The C386S variant and the protein expressed without FdsC were inactive in formate oxidation, supporting that both Moligands are essential for catalysis. Low-pH inhibition of RcFDH was attributed to protonation at the conserved His387, supported by the enhanced activity of the His387Met variant at low pH, whereas inactive cofactor species showed sulfido-to-oxo group exchange at the Mo ion. Our results support that the sulfido and S(Cys386) ligands at Mo and a hydrogen-bonded network including His387 are crucial for positioning, deprotonation, and oxidation of formate during the reaction cycle of RcFDH. Washington American Chemical Society 2015 12 Inorganic chemistry 54 7 3260 3271 10.1021/ic502880y Institut für Biochemie und Biologie OPUS4-38779 Wissenschaftlicher Artikel Spricigo, Roberto; Leimkühler, Silke; Gorton, Lo; Scheller, Frieder W.; Wollenberger, Ursula The Electrically Wired Molybdenum Domain of Human Sulfite Oxidase is Bioelectrocatalytically Active We report electron transfer between the catalytic molybdenum cofactor (Moco) domain of human sulfite oxidase (hSO) and electrodes through a poly(vinylpyridine)-bound [osmium(N,N'-methyl-2,2'-biimidazole)(3)](2+/3+) complex as the electron-transfer mediator. The biocatalyst was immobilized in this low-potential redox polymer on a carbon electrode. Upon the addition of sulfite to the immobilized separate Moco domain, the generation of a significant catalytic current demonstrated that the catalytic center is effectively wired and active. The bioelectrocatalytic current of the wired separate catalytic domain reached 25% of the signal of the wired full molybdoheme enzyme hSO, in which the heme b(5) is involved in the electron-transfer pathway. This is the first report on a catalytically active wired molybdenum cofactor domain. The formal potential of this electrochemical mediator is between the potentials of the two cofactors of hSO, and as hSO can occupy several conformations in the polymer matrix, it is imaginable that electron transfer from the catalytic site to the electrode through the osmium center occurs for the hSO molecules in which the Moco domain is sufficiently accessible. The observation of catalytic oxidation currents at low potentials is favorable for applications in bioelectronic devices. Weinheim Wiley-VCH 2015 6 European journal of inorganic chemistry : a journal of ChemPubSoc Europe 21 3526 3531 10.1002/ejic.201500034 Institut für Biochemie und Biologie